CONSOLIDATED STATEMENTS OF OPERATIONS (Parentheticals)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Series C [Member]
Preferred dividend rate	6.50%	6.50%	6.50%
Series D [Member]
Preferred dividend rate	7.55%	7.55%	7.55%